The present invention relates to a thin film component transfer method for transferring thin film components, such as thin film capacitors, formed on a supporting substrate transfer substrate. The present invention also relates to a circuit board provided with one or more transferred thin film components.
It is desired to provide combined modules incorporating ICs, capacitors, and inductors and passive modules with a low profile to be mounted on mobile communication devices such as cellular phones. For that purpose, for example, techniques for forming thin film capacitors with a high capacity on a printed board or resin substrate are desired. In order to form thin film capacitors on a non-heat resistant substrate such as Si interposer including polyimide or TSV, thin film capacitors must be formed at a temperature higher than the upper temperature limit of such a non-heat resistant substrate. Accordingly, thin film capacitors with a high dielectric constant are required to be formed at low temperature.
Japanese Patent Application Publication No. 2004-111400 teaches a multilayered printed circuit board using an thin film dielectric and manufacturing method thereof wherein a multilayered printed circuit board using it, and its manufacturing method wherein dielectric constant is 25 or more and a film thickness is 1.5 μm or less and an inorganic filler is dispersed in an organic resin. In addition, Japanese Patent Application Publication No. H9-148538 teaches a (Ba,Sr)TiO3 thin film capacitor and manufacturing method thereof wherein an organic metal compound solution composed of the main composition of (Ba,Sr)TiO3 and Si component of 0.1-10 mol % to the main component, 0.1-10 mol % is spread on a substrate to obtain thin film capacitor having a high sinterability at low temperature around 400° C. However, there are limitations in the above conventional methods associated with film formation temperature, which prevent obtaining thin film capacitors with a high capacity.
Another approach to obtain thin film capacitors with high capacity is to form a dielectric film by carrying out a heat treatment at a film formation temperature of 600° C. or more using a heat resistant substrate such as Si substrate. Such a high film formation temperature method may not use a non-heat resistant substrate such as polyimide substrate, epoxy substrate or TSV (Si through-hole electrode) substrate because such a non-heat resistant substrate is vulnerable to heat treatment at high temperature. Yet another approach is to transfer high dielectric thin film capacitors formed on a heat resistant substrate such as Si substrate to a different type of substrate at low temperature. For example, it is know to mechanically peel off a thin film capacitor formed on Si substrate and then transfer the peeled-off capacitor to a different type of substrate via a intervening layer (bonding layer) made of resin.
For example, Japanese Patent Application Publication No. 2008-4572 teaches a low cost dielectric structure and manufacturing method thereof. The dielectric structure, has a high dielectric constant and is formed on a necessary area without waste. The dielectric structure is formed by, prior to transfer, introducing a laminated SiO2/Pt structure (e.g., a structure comprising Ti or TiO2 for adhesiveness) having a high peeling characteristic into a base electrode on a heat resistant substrate which forms a dielectric film. Further, Japanese Patent Application Publication No. 2002-305334 teaches a functional thin film having a small amount of defects by easily and completely carrying out peeling on the interface between functional thin-film structure and a separation layer comprising metallic nitride by a substrate using the separation layer. Furthermore, Japanese Patent Application Publication No. 2008-166757 teaches an improvement of a transferring process using a laser lift-off process thereby providing an embedded printed board for thin film capacitors that can minimize damages to a dielectric film of the thin film capacitors.